Wet-strength paper comprising highly oxidized periodate oxystarch and process of preparing the same



May 18, 1965 J. w. SWANSON ETAL 3,184,333

WET-STRENGTH PAPER COMPRISING HIGHLY OXIDIZED PERIODATE OXYSTARCH AND PROCESS OF PREPARING THE SAME Filed Feb. 12, 1963 L c a, i ,LJ A

9I% OXIDIZED WHEAT STARCH STARCH BORAX,0

PER CENT WET TENSILE STRENGTH RAG PAPERS TUB SIZED WITH PERIODATE OXIDIZED STARCHES OOI x (EIIISNHJ. MICI/ BIISNHJ. 13M) l-usuauls 1.3M .LNBO 83d HTTMQNEX United States Patent 3,184,333 WET-STRENGTH PAPER COMPRISING HIGHLY OXIDIZED PERIODATE OXYSTARCH AND PROCESS OF PREPARING THE SAME John W. Swanson and Edward J. Jones, Appleton, Wis, and Charles L. Mehltretter, Peoria, 111., assignors to the United States of America as represented by the Secretary of Agriculture Filed Feb. 12, 1963, Ser. No. 258,090 3 Claims. (Cl. 117-156) This is a continuation-in-part of application Serial No. 779,036, filed December 8, 1958, now abandoned.

A non-exclusive, irrevocable, royalty-free license in the invention herein described, throughout the world for all purposes of the United States Government, with the power to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America.

This invention relates to paper which is characterized by greatly improved wet-strength properties and to a method of preparing the same by the use of dialdehyde starch (also called periodate oxystarch), which oxypolysaccharides comprise the subject matter of United States Patent No. 2,713,553 to Mehltretter, the disclosure of which patent is herewith incorporated by reference.

It is well known to improve the wet-strength of paper by subjecting the paper to an impregnating and coating composition comprising a synthetic resin such as melamine-formaldehyde or urea-formaldehyde.

Unexpectedly, it has now been found that the substitution of a dialdehyde starch composition in place of a synthetic resin dispersion applied by a conventional tubdip and hot-roll drying sequence greatly increases the wetstrength over that obtainable with the resin. The advantageous wet-strength superiority of paper treated with dialdehyde starch is shown by the data set forth in Tables .I and II and by the data of the drawing. It will also be apparent that the improved wet-strength property of the dialdehyde starch treated paper is stable to aging since there are no significant differences in the wet-strength valice termined 10 to 12 months after treating the paper, and the wet-strength values found in the remaining test items, which were performed within several days of the treatment.

An additional aspect of this invention is the discovery that the dispersability of the dialdehyde starch and both the wet-strength and dry-strength properties of the untreated paper are improved by first cooking the dialdehyde starch for about 30 minutes at up to 95 C. with a small percentage of borax or with a weakly acidic material such as a bisulfite or sulfurous acid, or with a weakly alkaline material such as a bicarbonate, a carbonate, or dilute sodium hydroxide. Conventional sizing agents may also be added to the treating composition when desired.

Although the results set forth in Tables I and II have been obtained by applying the dialdehyde starch as in a sizing bath, it is obvious that other modifications will be readily apparent to those skilled in the art.

The following example will illustrate our invention.

EXAMPLE 1 1.8 gm. (1.8 parts by weight) of borax (Na2B40q' were dissolved in 700 ml. water at room temperature, and gm. (50 parts by weight) of oven-dry corn starch that had been oxidized by periodic acid to the extent of 90 percent of theory was slowly added to the slightly alkaline dispersant solution with mechanical agitation which was continued while the periodate-oxystarch dispersion was heated on a steam bath up to 88 C. in 18 minutes. The clear dispersion was removed from the steam bath, cooled to room temperature, and enough water was added to bring the volume to 1,000 ml. and provide a paper-treating solution containing 5 percent by weight of the highly oxidized starch. The characteristics of paper sheets that were tub-sized in this solution are presented as item 6 (Institute of Paper Chemistry, File No. 177,253) of 'ues in items 1-2, 12, and 13 of Table I, which are de- 40 Table I.

Table l WET-TENSILE STRENGTH OF RAG PAPERS TUB-SIZED WITH PERIODATE-OXIDIZED STAROHES Schopper tensile in machine direction, lb./inch Oonccn- Uptake item No. I.P.C. Treatment tration of size, Wet

File No. size bath, percent percent Dry 5 min. 30 min. min. 4 hr. 8 hr. 16 hr. soaking soaking soaking soaking soaking soaking 173429 Untreated paper 25.1 4.0 4.0 3.9 1741 10 Untreated paper 27.0 4.1 3.9 3.7 173681 Stein, Hall Superfilm No. 4 5 2.4 29. 5 3.8 3. 2 3. 2 173430 95% oxidized cornstarch, 1.2% borax cook 5 2. 4 29. 5 14. 1 12. 6 12. 2 7. 8 7. 3 6, 2 177251 oxidized cornstarch, 1.8% borax coo 5 3.3 27.1 7.9 5.7 4.6 2.9 3.0

xi zed cornstarch, 3.6% borax cook 5 2. 8 27.1 6. 8 5. 2 4. 6 3.0 2. 6 178226 90% oxidized cornstarch, 1.8% borax cool 5 2.5 29.3 11.0 7.9 6.8 4.4 3.5 3.3 178330 96% oxidized cornstarch, 1.8% borax coo 5 2. 3 30.8 13.4 10.6 8.8 6. 3 5. 5 4. 7 178525 96% oxidized cornstarch, 1.8% cook,

air drie 5 2. 6 30. 5 12.1 11. 0 8. 8 5. 6 4. 7 4. 6 178526 96% oxidized cornstarch, 1.8% borax cook, short steam dry 5 2. 6 25. 5 14.6 0. 2 9. 3 5.3 4. 6 4. 5 178527 96% oxidized cornstarch, 1.8% borax cook, 5 min. steam dry 5 2. 6 26. 7 12.0 10. G 8. 7 6. 5 5. 2 4.8 173484 oxidizedcornstarch,bisulfitecook- 5 2.4 31.3 13.6 12.6 10.7 8.5 3.6 174141 96% oxidized cornstarch,bisulfite cook- 10 4.9 33. 0 17.3 16.6 14.7 9.6 7.7 5.8 178198 90% oxidizedcornstarch,bisultitecook 5 2.7 30.5 12.8 11.5 9.8 6.8 5.8 4.7 178331 96% oxidized cornstarch,hisulfite cook- 5 2.2 31. 7 13.7 12.2 11.0 8.8 7.5 6.4 178558 96% oxidized cornstarch, bisulfite cook, air dried 5 2. 2 30. 3 10.8 9.4 8. 4 6. 6 5. 8 4.8 178559 96% oxidized cornstarch, bisulfite cook, short steam dry 5 2. 2 30. 1 10. 9 8.8 8.7 6. 4 5. 4 5. 2 178860 96% oxidized cornstarch, bisulfite cook, 5 min. steam dry 5 2. 2 29. 3 11. 0 9.5 8.7 8. 3 5. 5 5. 5

, p 7 Table IContinued g V WET -TENSILE STRENGTH OF RAG PAPERS TUBrsIzED WITH PERIODATE-OXIDIZED STARCHES Schopper tensile in machine direction, 1b./inch V r Concen- Uptake Item N o. I.P.C. Treatment tration of size, Wet

File N 0. size bath, percent V percent Dry V r 5 min. 30 min. 60 min. 4 1n. 8 hr. 16 hr.

soaking. soaking soaking soaking soaking soaking 19 178750 1:1 ratio of (a) Peter Cooper TG220 glue containing 0.2% alum and (b) 96% oxidized cornstrach contaming 1.8% borax, air dried 5 3.0 31. 2 9.0 8.0 6. 9 5.8 I 5. 7 5. 5 As Item 19, short steemdry... 5 3. 5 33. 1 10.0 7.8 7. 6. 0 6. 0 5. 3 As'Item 19, min; steam dry 5 3. 5 33. 5 9. 6 8.8 7. 5 6.0 6.0 6. 0 1:1 ratio of (a) Peter Cooper TG220 glue, no alum, and (b) 88% oxidized cornstarch COntaining 1.8% borax, V p I air dried 5 3. 8 32.7 10.7 8. 8 7. 3 5. 7 5. 3 4.9 As Item 22, short steam dry e 5 3. 8 31.9 10. 4 "8. 8 7. 6 6.2 5. 9 5.2 AsItem 22, 5 min. steam dry 3.8 33. 6 10. 3 8. 7 8. 1' 6. 4 6. 5 5.8 93% oxidized waxy cornstarch, 1.8% r r Z borax cook 5 2.2 28.0 8.1 5.8 5.0 3.7 3.6 3.6 .AS Item 10 4.6 29.0 9.8 7.2 5.5 3.6 3.2 3.6 95% oxidized high amylose cornstarch, r

1.8% borax'cook 5 2. 3 28. 2 7. 9 6. 3 4.8 3. 7 3. 4 3. 5 'AsItem 27 10 4. 7 '30. 0 o 9. 7 6.8 5.3 3.7 3. 3 3. 6 91% oxidized wheat starch, 1.8% borax V V j cook 5 2.4 28.5 9.0 6. 5 4. 7 3. 8 3. 4 3.4 10 V 5. 1 26.6 10.6 7.7 5.9 3.8 3.4 3. 6 93% oxidized I fite cook; 5, n 2.0 29.5 i 14.1 12.1 g 10.1 7.5 5.6 5.0 Asltem 31.. 10 '4. 0 132. 0 17. 4 14.1 12. 1 9.0 7. 1 6. 4 95%-high amylase cornstarch, bisulfite I 'cook 5 2.1 31. 4 16.1 12. 1 11. 3, '815 6. 9 5. 6 As Item .10 4.1 32.9 17.7 14.5. 12.5 10.-l 7.8 7.2 91% Oxidized wheat starch 5 2. 3 33.3 17.7 14.8 14. 0 10. 7 7. 8 7. 2 AS Item 36--.; 10 4. 8 34. 2 20.0 16. 9 15. 5 12. 5 10. l 8. 3

Wet. strength, percent 7 Wet tensile treated paper r 7 r p 7 100 Concene Uptake Dry tensile treated paper Item No. I.P.C. Treatment 1 tration of size,

File No. q a size bath, 7 percent percent 5 min. min. min. 4 hr. 8 hr. 16 hr.

' V soaking soaking soaking soaking soaking soaking 1.- 173429 Untreated paper r r .15. 9 15. 9 15. 5'

Untreated paper 7 I 15.2 1 14. 5 13. 7 Stem, Hall Superfilm No. 4; 5 2. 4 12. 9 1 0. 9 10.9 95% oxidized cornstarch, 1.2% borax -coo 5 2.4 47.8 42.7 41 4 5 177254 oxidized cornstarch,'1.8% borax V V cook 5 3.3 r 29.2 21.1 17.0 6 177253 90% oxidized cornstarch,'3.6% borax o0 7 173226 90% oxidized cornstarch, 1.8% borax coo .1..... 2.5 37.5 27.0 23.2 8 173330 96% oxidized cornstarch, 1.8% borax I cook; 2*3 43.6 34;.5 28.6 9 173525 96% oxidized cornstarch, 1.8% .bor

cook, air 96% oxidized cornstarch cook, short steam dry 5 96% oxidized cornstarch, borax cook, 5 min. steam dr 5 oxidized cornstarch, bisulfite cook. 5 96% oxidized cornstarch, bisulfite cook. 10 90% oxidized cornstarch, bisuifite cook. 5 96% oxidized cornstarch, bisulfite cook- 5 96% oxidized cornstarch, bisulfite 5 .cook,,air drie 96% oxidized" cornstarch, bisulfite cook, short steam ry.. '5 2 2 35 9 29 0 23 6 21 1 17 8 17 1 96% oxidized cornstarch, bisulfite cook, ,5 min. steamdry .5 j 2 2 37 5 32 4 29 7 2s a 18 8 18 8 1:1 ratio of (a) Peter Cooper=TG220 glue containing 0.2% alum and (b) r v r 7 r 96% oxidized cornstarch containing 1.8% borax, air dried.-. As Item 19, short steam dry As Item 19, 5 min. steam dry.. 1:1 ratioof (a) Peter Cooper TG220 glue, no alum, and (b) 88% oxidized cornstarch containing 1.8% borax, air dried -1; 178790 As Item 22, short steam dry..- 178791 As Item 22, 5 min. steam dry 179271 93% oxidized waxy corn starch, 1.8%

borax cook 179272 As Item 25 V 179273 95% oxidized high amylose cornstarch 1.8% borax cook 179274 As Item 27 179269 91% oxidized wheat starch 1.

cook 179270 179809 lour Quinta v-ugrew 5 9".

pan

Table II WET-TENSILE STRENGTH OF WOOD PULP PAPERS HEATER-SIZED WITH SYNTHETIC RESINS Resin Schopper tensile lb'linch Wet tensile treated paper added, Dry tensile treated paper Item I.P.C. Treatment basis dry Wet No. File No. fiber,

percent Dry 5min. 30 min. 60 min. 4hr. 8hr. 16 hr. 5min. 4hr. 8hr. 16 hr. soaking soaking soaking soaking soaking soaking soaking soaking soaking soaking 1 178772 Control, 110115..-. 21.1 1.1 1.1 1.0 5.2 5.2 4.7 2 178775 Control, rosin 0 18.8 1.5 1.5 1.5 8.0 8.0 8.0

and alum. 3 178774 As Item 2, plus 2 19.7 5.8 5.8 6.0 29.5 29.5 30.5

melamineformaldehyde 165111. 4 178773 As Item3 3 21.0 7.7 7.6 7.0 7.6 36.7 36.2 33.3 36.2 5 Paper treated 3 12 l0 9 with cationic urea-formaldehyde resin.

Maxwell, 0. S., Tappi 35: 220-3 (1952). Having thus descr bed our lnvention, we claim: References Cited by the Examiner 1. A process for improving the wet-strength of paper which comprises dispersing about from 5 to 10 percent UNITED STATES PATENTS by Weight of substantially fully oxidized dialdehyde starch 2 7 7 39 Kemng 1 2 175 X in an aqueous solution containing about from 1.2 to 3.6 2,549,177 4 /51 Davidson 117 156 percent by weight of borax based on the dry weight of 2 606 188 8/52 Yenand 260 2333 the dialdehyde starch, heating the dispersion for about 2713553 7/55 Mghltretter 2O4 79 minutes at a temperature of about 95 C., soaking 2783283 2/57 Sloan et a1 "ig 3 paper in said dispersion, and then drying the paper.

2. A process for improving the wet-strength of paper which comprises dispersing about from 5 to 10 percent by weight of about from to 96 percent peri-odateoxidized starch in an aqueous solution containing about from 1.2 to 3.6 percent by weight of borax based on the dry Weight of the oxidized starch, heating the dispersion for about 30 minutes at a temperature up to C., soaking paper in said dispersion, and then drying the paper.

3. A high Wet-strength paper prepared by the process of claim 1, said paper containing dispersed therein about 2.8 percent based on the original weight of the paper of substantially fully periodate-oxidized dialdehyde starch.

OTHER REFERENCES RICHARD D. NEVIUS, Primary Examiner. 

1. A PROCESS FOR IMPROVING THE WET STRENGTH OF PAPER WHICH COMPRISES DISPERSING ABOUT FROM 5 TO 10 PERCENT BY WEIGHT OF SUBSTANTIALLY FULLY OXIDIZED DIALDEHYDE STARCH IN ANAQUEOUS SOLUTION CONTAINING ABOUT FROM 1.2 TO 3.6 PERCENT BY WEIGHT OF BORAX BASED ON THE DRY WEIGHT OF THE DIALDEHYDE STARCH, HEATING THE DIUSPERSION FOR ABOUT 30 MINUTES AT A TEMPERATURE OF ABOUT 95*C., SOAKING PAPER IN SAID DISPERSION, AND THEN DRYING THE PAPER. 